| From: | Claudio Freire <klaussfreire(at)gmail(dot)com> |
|---|---|
| To: | Jeff Janes <jeff(dot)janes(at)gmail(dot)com> |
| Cc: | postgresql(at)foo(dot)me(dot)uk, postgres performance list <pgsql-performance(at)postgresql(dot)org> |
| Subject: | Re: Slow query: bitmap scan troubles |
| Date: | 2012-12-05 17:43:49 |
| Message-ID: | CAGTBQpZa4Ru68pu6GiewBZUNk1hw8OObXaks6=Lt+-0qBdhjsg@mail.gmail.com |
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| Lists: | pgsql-hackers pgsql-performance |
On Wed, Dec 5, 2012 at 2:39 PM, Jeff Janes <jeff(dot)janes(at)gmail(dot)com> wrote:
> I'm not sure that this change would fix your problem, because it might
> also change the costs of the alternative plans in a way that
> neutralizes things. But I suspect it would fix it. Of course, a
> correct estimate of the join size would also fix it--you have kind of
> a perfect storm here.
As far as I can see on the explain, the misestimation is 3x~4x not 200x.
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